Increasingly complex networks of small RNAs act through RNA-interference (RNAi) pathways to regulate gene expression, to mediate antiviral responses, to organize chromosomal domains, and to restrain the spread of selfish genetic elements. Historically, RNAi has been defined as a response to double-stranded RNA. However, some small RNA species may not arise from double-stranded RNA precursors. Y...

Many genetic neurological diseases result from the dysfunction of single proteins. Genetic therapies aim to modify these disease-associated proteins by targeting the RNA and DNA precursors. This review provides a brief overview of the main types of genetic therapies, with a focus on antisense oligonucleotides (ASOs) and RNA interference (RNAi). We use examples of new genetic therapies for spina...

RNA interference (RNAi) is an evolutionarily conserved mechanism in plant and animal cells that directs the degradation of messenger RNAs homologous to short double-stranded RNAs termed small interfering RNA (siRNA). The ability of siRNA to direct gene silencing in mammalian cells has raised the possibility that siRNA might be used to investigate gene function in a high throughput fashion or to...

RNA-mediated gene interference (RNAi), a rapid, convenient tool for inhibiting gene function in Caenorhabditis elegans, has recently been shown to work in other organisms.

RNA silencing, including gene quelling in fungi and RNA interference in animals, refers to a process of homologous, sequence-specific, RNA-based, post-transcriptional gene silencing triggered by double-stranded RNA that requires a conserved set of gene products. RNA-induced, homology-dependent gene silencing can also spread locally and systemically between cells to orchestrate developmental pro...

RNA interference (RNAi) is a phenomenon in which double-stranded RNA (dsRNA) silences endogenous gene expression. By injecting pools of dsRNAs into Caenorhabditis elegans, we identified a dsRNA that acts as a potent suppressor of the RNAi mechanism. We have used coinjection of dsRNAs to identify four additional candidates for genes involved in the RNAi mechanism in C. elegans. Three of the gene...

Over the past two decades, dramatic advances in the role of RNA in normal health and disease have been greatly expanded. During development Small RNA molecules regulate eukaryotic gene expression and also during responses to stress including viral infection. RNA interference (RNAi) is a highly conserved process in eukaryotes that leads to post-transcriptional gene silencing through degradation ...

A recent study by Massirer et al. in the nematode C. elegans has shown that a family of microRNAs (miRNAs), miR-35-41, regulates the efficiency of RNA interference (RNAi), revealing a new connection between these small RNA pathways. In this commentary, we discuss the potential mechanisms for cross regulation in the miRNA and RNAi pathways and the implications for gene expression. While miRNAs a...

Approximately all sequenced archaeal and half of eubacterial genomes have some sort of adaptive immune system, which enables them to target and cleave invading foreign genetic elements by an RNAi-like pathway. CRISPR–Cas (clustered regularly interspaced short palindromic repeats–CRISPR-associated proteins) systems consist of the CRISPR loci with multiple copies of a short repeat sequence separa...

In October 2006, Andrew Z. Fire (Stanford University School of Medicine) and Craig C. Mello (University of Massachusetts Medical School) were awarded the Nobel Prize in Physiology or Medicine 2006 for their discovery of RNA interference (RNAi)—gene silencing by doublestranded DNA (http://nobelprize.org/). We have compiled an overview of this new technology, addressing the basic concepts of ribo...